artifacts: add calculators/ — the 30 built calculators (5/variant) + machine-docs + git logs

calculators/builder-adversary-min/run-04/machine-docs/JOURNAL-parse.md

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+# JOURNAL-parse
+
+## Design decisions
+
+- **Grammar**: classic 3-level recursive descent:
+  - `expr → term (('+' | '-') term)*` (lowest precedence)
+  - `term → unary (('*' | '/') unary)*` (medium)
+  - `unary → '-' unary | primary` (right-recursive for stacked unary)
+  - `primary → NUMBER | '(' expr ')'`
+- Left associativity falls out naturally from the `while` loops in `_expr` and `_term`.
+- Unary is right-recursive (`-` `-` 5 → nested Unary) as is conventional.
+- Empty input detected early at `parse()` entry before any descent.
+- Trailing tokens detected after `_expr()` returns, before EOF check.
+
+## Test count: 31 (20 parser + 11 existing lexer)